PARIS, Jan 16 (Reuters) - French construction company Vinci is confident it will be compensated if the government scraps a plan to build a new airport near the western city of Nantes.

President Emmanuel Macron’s government has promised a final decision by the end of the month on whether to build a new airport at Notre Dame des Landes -- an idea dating back more than three decades -- or expand an existing one on the outskirts of Nantes.

Vinci has a 55-year concession to build and operate the planned 580 million euro ($709 million) new airport.

One of three experts who reviewed the two options said in a report presented to the government last month that compensation due to Vinci could amount up to 350 million euros.

Some French media have reported that the government was seeking ways to avoid paying damages to Vinci should it pull the plug on the Notre Dame des Landes project.

“The state felt the need through a few phone calls to tell us that this was completely false,” Chief Executive Xavier Huillard said, speaking at a company presentation held on the site of a Paris metro line extension Vinci is working on.

He declined to give details on how much a potential award might amount to. Opponents of the new airport say it is too costly, bad for the environment and not needed because other airports in the wider region have spare capacity.

In his presentation, Huillard reiterated forecasts for higher 2017 revenue driven by a recovery in its contracting business and a solid performance of its motorways and airport concessions.

He also confirmed Vinci could increase its 8 percent stake in Aeroports de Paris (ADP) if the French state decides to privatise the airports operator or sell part of its stake. “ADP is an issue of interest to us but no one knows what the state will decide. We think there will be some action in 2018,” Huillard said.

The government has begun reducing its corporate holdings to finance a 10 billion euros fund for investment in innovation. While it has not revealed all the stakes which will be sold, sources expect ADP will be included. ($1 = 0.8185 euros) (Reporting by Dominique Vidalon; Editing by Richard Lough and Keith Weir)